1. Field of the Invention
The invention relates generally to a storage system on which high security requirements are imposed and a method for the storage system, and is particularly suited to utilization in a technique for managing pairs, including both volumes recognized and volumes not recognized by a management computer or a host computer, together.
2. Description of Related Art
Examples of control systems employing storage apparatuses include an out-of-band system in which: a storage apparatus handles the control information that has passed through a network; and data is directly transferred between a host system such as a management computer or a host computer and the storage apparatus, and an in-band system in which a storage apparatus handles the control information and the data that have both passed through a data communication line. In a storage system on which high security requirements are imposed, employing an out-of-band system involves the risk that a host system sees the configurations and content of all the volumes in a storage apparatus. Therefore, the employment of in-band system is becoming more established.
Meanwhile, the continuity of a storage system and the data itself handled in the storage system have been growing in importance with the spread of information technology (IT). Therefore, the demand for protection for a storage system against unexpected situations such as terrorism and natural disaster is increasing. One of the techniques to meet the demand is disaster recovery. In disaster recovery, as disclosed in JP11-085408 A, data in a storage system is copied; the copied data is transferred to a remote place to be stored; and accordingly, it is possible for the storage system to be recovered even after the occurrence of a fault in the storage system due to a disaster, for example.
Also, in recent years, storage systems have been increasing in size, and there has been demand for the utilization of disaster recovery techniques in storage systems composed of plural host computers. In the above storage system, specific volumes in each of the host computers may be accessible for data in order to maintain data integrity for the host computers.
In light of the above, as disclosed in JP2005-196618 A, in order to achieve copy control targeted to all the volumes in the entire storage system using an in-band system, specific volumes to which data access is permitted and volumes to which data access is not permitted are included in one group, and giving a copy instruction to the group provides a management computer with a copy control interface on a group basis. As a result, copy can be conducted also for the volume that cannot be accessed by an arbitrary host computer.
Also, as disclosed in JP2007-102455 A, there is an in-band system technique in which a management computer can conduct copy control for an arbitrary volume via a special accessible volume (command device) in a storage apparatus. With this technique, the management computer specifies a logical volume address (hardware address) for a storage system with respect to a control target volume and issues a storage control command, enabling copy control for an arbitrary volume.
Plural host computers and one management computer conducting copy control for disaster recovery in a storage system using an in-band system will be discussed.
According to JP2005-196618 A, in a storage system with connected host computers, plural volumes including a copy control target volume are grouped, and this enables a management computer to achieve copy control collectively for the volumes requested by the respective host computers. However, according to the technique in JP2005-196618 A, copy control conducted by the management computer with respect to the volumes in the group is achieved, but copy control for an arbitrary volume cannot be conducted irrespective of whether the volume is in or out of the group.
Moreover, according to JP2007-102455 A, a storage control command needs to be issued to a command device in a storage system in order to enable copy control for an arbitrary volume; however, copy control cannot be performed originally for a volume not recognized by a management computer.